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From: Jakub Kicinski <kuba@kernel•org>
To: Stephen Hemminger <stephen@networkplumber•org>
Cc: Cong Wang <xiyou.wangcong@gmail•com>,
	netdev@vger•kernel.org, William Liu <will@willsroot•io>,
	Savino Dicanosa <savy@syst3mfailure•io>
Subject: Re: [Patch net v6 4/8] net_sched: Implement the right netem duplication behavior
Date: Sun, 4 Jan 2026 11:19:12 -0800	[thread overview]
Message-ID: <20260104111912.66940630@kernel.org> (raw)
In-Reply-To: <20251230092850.43251a09@phoenix.local>

On Tue, 30 Dec 2025 09:28:50 -0800 Stephen Hemminger wrote:
> It is worth testing for the case where netem is used as a leaf qdisc.
> I worry that this could cause the parent qdisc to get accounting wrong.
> I.e if HTB calls netem and netem queues 2 packets, the qlen in HTB
> would be incorrect.

Indeed, presumably backlog should be corrected with
qdisc_tree_reduce_backlog() ? Either way it'd be great to add / adjust 
some test cases to confirm backlogs are 0 after the traffic stopped.

  reply	other threads:[~2026-01-04 19:19 UTC|newest]

Thread overview: 16+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2025-12-27 19:41 [Patch net v6 0/8] netem: Fix skb duplication logic and prevent infinite loops Cong Wang
2025-12-27 19:41 ` [Patch net v6 1/8] net_sched: Check the return value of qfq_choose_next_agg() Cong Wang
2025-12-30 17:24   ` Stephen Hemminger
2025-12-27 19:41 ` [Patch net v6 2/8] Revert "net/sched: Restrict conditions for adding duplicating netems to qdisc tree" Cong Wang
2025-12-27 19:41 ` [Patch net v6 3/8] Revert "selftests/tc-testing: Add tests for restrictions on netem duplication" Cong Wang
2025-12-27 19:41 ` [Patch net v6 4/8] net_sched: Implement the right netem duplication behavior Cong Wang
2025-12-30 17:28   ` Stephen Hemminger
2026-01-04 19:19     ` Jakub Kicinski [this message]
2026-01-07 23:33     ` Cong Wang
2026-01-08  2:18       ` Jakub Kicinski
2025-12-27 19:41 ` [Patch net v6 5/8] selftests/tc-testing: Add a nested netem duplicate test Cong Wang
2025-12-27 19:41 ` [Patch net v6 6/8] selftests/tc-testing: Add a test case for piro with netem duplicate Cong Wang
2026-01-04 19:15   ` Jakub Kicinski
2026-01-07 23:34     ` Cong Wang
2025-12-27 19:41 ` [Patch net v6 7/8] selftests/tc-testing: Add a test case for mq " Cong Wang
2025-12-27 19:41 ` [Patch net v6 8/8] selftests/tc-testing: Update test cases " Cong Wang

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